Recent advances in human genomics research have led to rapid progress in the identification of novel and/or previously unidentified genes. In applications to biological and pharmaceutical research, there is a further need to determine the function of such identified gene products. A first step in defining the function of a novel gene is to determine its interactions with other gene products in an appropriate context. Since proteins make specific interactions with other proteins or biopolymers as part of functional assemblies or physiological pathways, a representative way to examine the function of a gene is to determine its physical relationship to one or more other genes.
Aging is a complex physiological phenomenon and the link between genes that regulate longevity and stress response is of great interest in the field of aging-related disorders such as diabetes, cancer, osteoporosis, cardiovascular and neurodegenerative diseases. The “free radical” theory of aging (Harman, (2001) Ann. N.Y. Acad. Sci. 928:1–21), and the central role that mitochondria play in this process, is gaining recognition. Proof of principle has been established in model systems such as C. elegans, Drosophila and recently in mouse (Guarente & Kenyon, (2000) Nature 408:255–62; Hayflick, (2000) Nature 408: 267–9; Lithgow & Andersen, (2000) Bioessays 22:410–3). Certain signaling pathways involved in the regulation of cell growth also participate in cellular response to oxidative stress (Zachary & Gliki, (2001) Cardiovasc. Res. 49:568–81). Growth factor receptors such as EGFR and PDGFR are activated on exposure to hydrogen peroxide (H2O2) (Kamata et al., (2000) Eur. J. Biochem. 267:1933–44). Activation of these receptors results in the recruitment and assembly of multiprotein signaling complexes at the membrane that ultimately result in gene expression changes that determine cellular fate (for a review, see, e.g., Liebmann, (2001) Cell Signal 13:777–85). One of the key mitogenic adapter proteins involved in this pathway is the Src Homologous Collagen-homologous protein, Shc family adapter protein (Ravichandran (2001) Oncogene 20:6322–30). The ShcA locus is highly conserved throughout evolution and encodes three overlapping proteins of 66, 52 and 46 kDa (Luzi et al., (2000) Curr. Opin. Genet. Dev. 10:668–74). Molecular and biochemical evidence suggests a role for p52/p46ShcA in receptor tyrosine kinase (RTK)-mediated signal transduction and activation of the Ras/MAPK pathway.
The most recently defined member of the family, p66ShcA is an anomaly in the mitogenic activity of ShcA (Bonfini et al., (1996) Trends. Biochem. Sci. 21:257–61). It differs from the other two ShcA proteins (p52/p46ShcA) in that it has a second proline/glycine-rich domain (CH2) at the amino-terminus, which appears to confer different properties to this ShcA family member. Evidence suggests a role for it in stress pathways activated by insults such as UV irradiation and oxidation (Migliaccio et al., (1999) Nature 402:309–13).
Despite these advances, there continues to be a need in the art to identify protein-protein interactions that are involved in mammalian physiological disorders and diseases, and to thereby identify therapeutic targets for drug discovery.
The publications and other materials referenced herein by author to illuminate the background of the invention or to provide additional details regarding the practice of the invention, are incorporated by reference in their entirety.